Jerome Gambit: Light-Hearted Calculations

 

The other day I took a trip back in time, to some blog posts from a dozen years ago. In "The Jerome Gambit: Helping or Hurting?" I had written

Looking at The Database today, I noticed that I had played 250 rated games with the Jerome Gambit (1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+).

My score was 83%, which I thought was pretty good. 

Then I wondered: maybe I scored well because I simply played my refuted opening against weaker players...

So, I looked at my average rating for those games, and the average rating of my opponents, and it was true: my opponents were, generally, weaker. 

By about 65 rating points. 

That would mean that instead of playing equally-rated opponents and expecting to score 50%, I was playing slightly weaker opponents, and was expected to score about 60%. 

Ooops! 

With the Jerome Gambit I was still scoring 23% higher than expected.

 

Today, The Database shows that I have played 449 games with 1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+, scoring 82% - remarkably consistent with the previous number.

In the current statistics, I averaged being rated about 140 points above my opponent. (Again, this is not surprising, as in many games I was giving "Jerome Gambit odds".) The expectation is that I would score 69%. Instead, I scored 13% higher than expected.

A similar look at The Database for the Italian Four Knights Jerome Gambit, 1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Nc3 Bc5 4.Bxf7+, shows 72 games, with my expected score (based on the difference between average ratings) being 60% - while it was actually 75%, 15% higher than expected.

When it comes to the Blackburne Shilling Jerome Gambit, 1.e4 e5 2.Nf3 Nc6 3.Bc4 Nd4 4.Bxf7+, in 46 games my expected score was 57%, while my actual score was 90% - a solid 33% higher.

Finally, as for the Semi-Italian Jerome Gambit, 1.e4 e5 2.Nf3 Nc6 3.Bc4 h6 4.0-0 Bc5 5.Bxf7+, in 61 games my expected score was 54%. while my actual score was 89% - 45% higher.

So: Why do I continue to play the Jerome Gambit?

Of course, because it is fun.

But, also, because it helps me perform above expectations.